Charles Crawford was British Ambassador in Sarajevo, Belgrade and Warsaw before leaving the Foreign Office in 2007 to become an international relations consultant and speechwriter. He is a founder member of The Ambassador Partnership. His own website is Charles Crawford and he is on Twitter @CharlesCrawford

As a former ambassador, I hope and expect that Manning will get a long and miserable prison sentence

Here is a silly if not mentally ill squirt who abused a position of trust and leaked vast quantities of American classified material, most of it things he could not even have read. He had no idea of the damage to other people he might cause. Let him rot in prison, perhaps comparing notes with another clever bonehead, my former classmate at the Fletcher School of Law and Diplomacy Jay Pollard. Pollard was an actual spy, systematically stealing material deliberately to pass it on to Israel. Down he went in 1986. Maybe due out in 2015?

On the other hand, what about the argument that Manning brought to public attention various grave abuses? Where does that fit in?

One feature of the United States of America is that it takes free speech seriously and also makes ginormous provision for "whistleblowing" – giving legal and procedural protection to people who find out that something is wrong where they work and reveal the facts. Does any country in the world have anything remotely similar? We don't. On top of that there will be all sorts of codes and procedures within even the US Army to help people report things that are out of order.

So, Manning had options. If he found material that was clearly compromising or revealing illegal activity, he could have used those procedures. However, he might reasonably have feared that some of the material was so damaging that anything he said would be suppressed and indeed that he would be suppressed too.

So an alternative route would be to take copies of the material concerned, squirrel them away in cyberspace or otherwise, and then walk round to a leading media outlet to tell them what he had done and perhaps to give them a copy, then walk back to the Army and hand himself in. You can build in to the arrangement certain triggers for more and more material to be leaked if you are not treated properly. This way the key compromising material could be leaked but under controlled and responsible conditions.

What makes no sense at all unless you are a simple wrecker or moron is to copy vast impossible swathes of classified material without knowing what is in it then dump it on the Internet. It's not clear to me how far he was bamboozled or lured into doing this by Wikileaks/Assange.

Apart from anything else, this madcap mass dumping of information compels the state to treat you harshly to discourage others from doing the same. It makes it impossible to argue that you are motivated by any systemic principle based on taking the existing generous whistleblower provisions seriously on their own terms and acting as a loyal principled insider. It betrays colleagues.

That's why I hope and expect that Manning will get a long and miserable prison sentence. It's too easy to point out the contrast between this deluded dimwit and Vasili Mitrokhin who for year after year worked tirelessly deep within a horrendous and unjust Soviet KGB system in the hope of one day getting his leaked information out. But I'll do it anyway.

A true democracy wants to encourage people who work for it to think hard about the moral and wider context of their work: things can go badly wrong in policy work, and official staff are a key line of defence. See NHS and BBC payoffs to people not to talk. Horrible abuse of public funds. The knowledge that there are powerful whistleblowing rules and other fair ways to compel Top Brass to face up to abuses under their leadership is a key discipline for everyone and a huge benefit to taxpayers. Manning cut across all that in his recklessness.

I can think of only one occasion in my own career as a diplomat where I saw Top Secret FCO papers clearly pointing to an earlier grave official abuse of power. Not really knowing the whole story, I did nothing about them. Perhaps I was wrong. I wonder to this day whether when my own moment came I ducked a key moral challenge.

Still, I did not sneakily copy thousands of FCO Top Secret documents and throw them out of the window to flutter across St James's Park, betraying myriad national and international confidences to the four winds. That's not right, either